Billick, the Super Bowl-winning coach now an NFL analyst for Fox Sports, will be part of the team broadcasting the Vikings’ game in Detroit on Sunday. So he has watched both teams, analyzed their 2012 seasons, gotten up to speed on both rosters.

And yet, when asked a simple question, he paused.

Who would you take first? Vikings running back Adrian Peterson, who came within a whisper of setting the single-season rushing record last season? Or Lions receiver Calvin Johnson, who set the receiving yards record last season?

“Well, that’s a tougher question to answer than it would seem,” Billick said, “though I agree that you’re talking about the best players in the game today at their position.”

Do you go with Peterson’s 2,097 rushing yards, his league-best 2,314 yards from scrimmage, his incredible 1,019 yards after contact? Or do you go with Johnson’s 1,964 receiving yards, the fact that he is only the fifth player in league history to reach 7,500 career yards in 90 or fewer games?

Do you marvel at Peterson’s incredible 27 rushes of 20 or more yards? Or Johnson’s 40 catches of 20 or more yards?

Not an easy decision. But Sunday’s opener for both teams will include both dominant players.

Both of them were drafted in the first round of the 2007 draft (Johnson second overall, Peterson seventh); both transitioned quickly to the NFL. Peterson has scored 80 touchdowns, Johnson 55.

Each has kept track of the other since being drafted on the same day.

“AP’s the man,” Johnson said. “I mean, what he does, with all the carries he gets, all the punishment? Well, he doesn’t really take punishment, he dishes it out. … I just hope he doesn’t do it against us.”

Said Peterson: “Definitely have a great appreciation for him. [He is a] great talent, a guy that you have to account for.”

Both are used to being the focus of opposing defenses but have managed to dominate nonetheless.

So, which player would you choose? “If you look just at the stats, I would lean toward Adrian Peterson,” Billick said. “He touches the ball 30, 35 times a game. I think that gives him a much bigger impact than a guy who, in a good game, will have 10 to 12 receptions.”

Others agree. Jimmy Johnson won two Super Bowls while coaching a Dallas team that had future Hall of Famers at quarterback (Troy Aikman), running back (Emmitt Smith) and receiver (Michael Irvin).

So which player would he take to start a team? “Well, I wouldn’t take either one,” Johnson said of Peterson and Johnson. “I’d take a quarterback first. And then my second choice would be another quarterback. But as far as those two players? The running back. He’s going to have an impact on the game, regardless. The receiver is relying on having a good quarterback. If I were forced to take one of the two without the quarterback, I’d take the healthy running back.’

Said Aikman: “I would as well. Having played with some great receivers, those guys have a huge impact, no question. But you can do things, slow them down a little — though nobody did it with Calvin, I have to admit. Still, I’d go with [Peterson].”

There is a caveat. Peterson got his team into the playoffs last season despite an uneven passing attack. Johnson racked up the numbers for a disappointing 4-12 team. Still …

“Unfortunately, today the adage of running the ball and playing good defense isn’t enough to win championships,” Billick said. “You’d have to run the ball and lead the league in defense. So the big question is whether [Christian] Ponder is good enough to complement the most impactful player in the league?”

The answers will start coming on Sunday.

The Vikings have tried to improve their passing game with an upgrade at receiver. The Lions have tried to balance their pass-happy attack with the addition of running back Reggie Bush.